The present invention relates in general to electrical power tools, and more particularly to a multipurpose rechargeable power tool with a main body portion for connection to various different types of interchangeable tool heads.
The electric tool is a common tool with very widespread applications in households and factories. In the past, it has often been necessary to purchase multiple tools in order to perform multiple processes or operations such as drilling, planing, shearing, grinding, and like, resulting in high purchase cost and carrying inconvenience. In order to overcome the drawbacks of high purchase expense and carrying inconvenience, many patents and documents have covered various forms of combination electric tools.
Chinese Patent No. ZL93220617.4, for example, discloses a type of electric tool assembly, wherein a main machine part of an electric motor is coupled with multiple different tool heads to drive different kinds of tools, so as to provide multipurpose functioning with one machine. However, that patent does not disclose how the tool head is coupled with the main machine part.
Chinese Patent No. ZL97201237.0, for example, discloses a combination type multipurpose electric tool, and sets forth a method of coupling the main machine part with tool head. It can be noted from the technique disclosed by that patent, that the main machine part and tool head utilize male and female screw threads to make the coupling. This kind of coupling method is very inconvenient when replacing tool heads, and makes it easy to damage the output shaft or electric motor.
Presently, electric power tools on the market include direct coupling of the electric motor with a tool head, utilizing a close fit between both to accomplish this process. However, despite the simple arrangement, the coupling is of low sustaining force, of rather inferior reliability, low safety, and is thus inadvisable for use.
It can be clearly noted from the conditions of the above-mentioned disclosed patent techniques and market products, that the method of coupling multipurpose tool heads with one machine has become the crux of multipurpose combination tools.
It is an object of the present invention to provide a charging type multipurpose combination tool that includes a main body portion having an electric motor, a speed control switch and battery set, that can be releasably coupled to a tool head portion through a locking mechanism, so as to overcome the above-mentioned drawbacks of the prior art.
The present invention divides the existing electric tool into a main body portion and a tool head portion. The main body portion may include an electric motor, a speed control switch, a battery and the like components, while the tool head portion may be provided with a speed control device, a direction control device, a transmission mechanism and the like components. The above-mentioned elements are all prior art and therefore will not be further described. The main body portion couples with the tool head portion through a locking mechanism.
The locking mechanism comprises an external spline with guiding faces fixed on the electric motor output shaft through conventional mechanical means, an internal spline integrally connected to the transmission mechanism inside the tool head portion, a locking piece rotatable over a predetermined distance, a locking head, and the like components.
The locking piece includes wedge-shaped faces with guide tabs to facilitate rotation of the locking piece. The locking piece is sleeved at the outer side of the external spline and is rotatable in the clockwise and counterclockwise directions over a predetermined distance. The locking piece is coupled with a locking thrust ring fixed on the housing of the main body portion.
The locking head is provided at the outer side of the internal spline, and is fixed on the housing of the tool head portion. Bosses are provided at an end portion of the tool head portion, and a wedging slot is formed between the bosses and the housing of the tool head portion. The wedge-shaped faces of the locking piece and the bosses of the locking head releasably lock together to thereby releasably lock the tool head portion to the main body portion.
The internal and external splines mate with each other to transmit electric motor power to the tool head portion. The tool head portion may be provided with convex strips at an end portion thereof. The convex strip preferably mate with concave slots provided at an inner side of a front end of the main body portion to enable the tool head portion to be easily inserted into the main body portion.
The present invention can form different tools with a single main body portion and different interchangeable tool head portions by merely changing one tool head portion for another. The tool head portions can be in the form of an electric drill head assembly to be rapidly used as an electric drill; the tool head portion can be in the form of a triangular sanding head assembly to be used as a sanding machine; the tool head portion can be in the form of an angular grinding machine head assembly to be used as angular grinding machine; the tool head portion can be in the form of a cement or concrete mixing assembly to be used as a cement concrete mixing machine; the tool head portion can be in the form of a reciprocating-type sawing machine to be used as reciprocating sawing machine, and so on. The various tool head portions mentioned above are well known and, in accordance with the present invention, can be easily connected to and disconnected from the main body portion.
It can be noted clearly from the above that the electric tool of the present invention can overcome the disadvantages associated with single-purpose electric power tools by providing a multipurpose power tool with a single motor and interchangeable tool heads that can be quickly and conveniently connected and disconnected to the motor, and can be easily carried.